Evaluation of Pipeline Flex delivery system for the treatment of unruptured aneurysms

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Multicenter Study of Pipeline Flex for Intracranial Aneurysms

BACKGROUND

The Pipeline Flex (PED Flex; Medtronic, Dublin, Ireland) was designed to facilitate deployment and navigation compared to its previous iteration to reduce the rate of technical events and complications.

OBJECTIVE

To assess the neurological morbidity and mortality rates of the PED Flex at 30 d.

METHODS

Information from 9 neurovascular centers was retrospectively obtained between July 2014 and March 2016. Data included patient/aneurysm characteristics, periprocedural events, clinical, and angiographic outcomes. Multivariate logistic regression was performed to determine predictors of unfavorable clinical outcome (modified Rankin Scale [mRS] > 2).

RESULTS

A total of 205 patients harboring 223 aneurysms were analyzed. The 30-d neurological morbidity and mortality rates were 1.9% (4/205) and 0.5% (1/205), respectively. The rate of intraprocedural events without neurological morbidity was 6.8% (14/205), consisting of intraprocedural ischemic events in 9 patients (4.5%) and hemorrhage in 5 (2.4%). Other technical events included difficulty capturing the delivery wire in 1 case (0.5%) and device migration after deployment in another case (0.5%). Favorable clinical outcome (mRS 0-2) was achieved in 186 patients (94.4%) at discharge and in 140 patients (94.5%) at 30 d. We did not find predictors of clinical outcomes on multivariate analysis.

CONCLUSION

The 30-d rates of neurological morbidity and mortality in this multicenter cohort using the PED Flex for the treatment of intracranial aneurysms were low, 1.9% (4/205) and 0.5% (1/205), respectively. In addition, technical events related to device deployment were also low, most likely due to the latest modifications in the delivery system.

Prospective study on embolization of intracranial aneurysms with the pipeline device: the PREMIER study 1 year results

Background

Preliminary clinical studies on the safety and efficacy of the pipeline embolization device (PED) for the treatment of small/medium aneurysms have demonstrated high occlusion rates with low complications.

Objective

To evaluate the safety and effectiveness of the PED for treatment of wide necked small and medium intracranial aneurysms.

Methods

PREMIER is a prospective, multicenter, single arm trial. Patients were treated with the PED for unruptured wide necked aneurysms, measuring ≤12 mm along the internal carotid artery or vertebral artery, between July 2014 and November 2015. At 1 year post-procedure, the primary effectiveness endpoint was complete occlusion (Raymond grade 1) without major parent vessel stenosis (≤50%) or retreatment, and the primary safety endpoint was major stroke in the territory supplied by the treated artery or neurologic death.

Results

A total of 141 patients were treated with PEDs (mean age 54.6±11.3 years, 87.9% (124/141) women). Mean aneurysm size was 5.0±1.92 mm, and 84.4% (119/141) measured <7 mm. PED placement was successful in 99.3% (140/141) of patients. Mean number of PEDs implanted per patient was 1.1±0.26; a single PED was used in 92.9% (131/141) of patients. At 1 year, 97.9% (138/141) of patients underwent follow-up angiography with 76.8% (106/138) of patients having met the study’s primary effectiveness endpoint. The combined major morbidity and mortality rate was 2.1% (3/140).

Conclusions

Treatment of wide necked small/medium aneurysms with the PED results in high rates of complete occlusion without significant parent vessel stenosis and low rates of permanent neurologic complications.

Trial registration

NCT02186561.

Periprocedural complications of second-generation flow diverter treatment using Pipeline Flex for unruptured intracranial aneurysms: a systematic review and meta-analysis

Background

Flow diverters are a breakthrough treatment for large and giant intracranial aneurysms but carry a risk of periprocedural death or major stroke. Pipeline Flex is a second-generation device that is thought to have lower complication rates because of improvements in the delivery system as well as increased operator experience. Our objective was to analyze the risk of periprocedural death or major complications using Pipeline Flex for unruptured intracranial aneurysms.

Methods

A systematic search of three databases was performed for studies of ≥10 treatments using Pipeline Flex for unruptured intracranial aneurysms (2014–2019) using PRISMA guidelines. Random effects meta-analysis was used to pool the rates of periprocedural (<30 days) death, major ischemic stroke, symptomatic intracranial hemorrhage, and minor stroke/transient ischemic attack.

Results

We included eight studies reporting 901 treatments in 879 patients. Periprocedural mortality (<30 days) was 0.8% (5/901; 95% CI 0.4% to 1.5%; I2=0%). Rate of major complications (death, major ischemic stroke, or symptomatic intracranial hemorrhage) was 1.8% (14/901; 95% CI 1.0% to 2.7%; I2=0%). Aneurysm size ≥10 mm was a statistically significant predictor of a major complication (OR 6.4; 95% CI 2.0 to 20.7; p=0.002). Risk of a major complication in aneurysms <10 mm was 0.9% (95% CI 0.3% to 1.7%; I2=0%). The meta-analysis was limited by the predominance of anterior circulation aneurysms.

Conclusion

Treatment of unruptured intracranial aneurysms using the Pipeline Flex flow diverter has a low periprocedural risk of death (0.8%) or major complication (1.8%). The risk of a major complication is significantly higher for large/giant aneurysms (4.4%) and is very low for aneurysms <10 mm (0.9%).

On Flow Diversion: The Changing Landscape of Intracerebral Aneurysm Management

Uptake of flow-diverting technology is rapidly outpacing the availability of clinical evidence. Most current usage is off-label, and the endovascular community is nearer the beginning than the end of the learning curve, given the number of devices in development. A comprehensive overview of technical specifications alongside key outcome data is essential both for clinical decision-making and to direct further investigations. Most-studied has been the Pipeline Embolization Device, which has undergone a transition to the Pipeline Flex for which outcome data are sparse or heterogeneous. Alternative endoluminal devices do not appear to be outperforming the Pipeline Embolization Device to date, though prospective studies and long-term data mostly are lacking, and between-study comparisons must be treated with caution. Nominal technical specifications may be unrelated to in situ performance, emphasizing the importance of correct radiologic sizing and device placement. Devices designed specifically for bifurcation aneurysms also lack long-term outcome data or have only recently become available for clinical use. There are no major studies directly comparing a flow-diverting device with standard coiling or microsurgical clipping. Data on flow-diverting stents are too limited in terms of long-term outcomes to reliably inform clinical decision-making. The best available evidence supports using a single endoluminal device for most indications. Recommendations on the suitability and choice of a device for bifurcation or ruptured aneurysms or for anatomically complex lesions cannot be made on the basis of current evidence. The appropriateness of flow-diverting treatment must be decided on a case-by-case basis, considering experience and the relative risks against standard approaches or observation.

Early Versus Delayed Flow Diversion for Ruptured Intracranial Aneurysms: A Meta-Analysis

OBJECTIVE

The use and timing of flow diversion for aneurysmal subarachnoid hemorrhage is controversial. The objective of this study is to perform a meta-analysis and systematic review to compare overall complication rate between early versus delayed flow diversion for ruptured aneurysms.

METHODS

A literature search for all eligible articles was performed using PubMed, Cochrane, and Web of Science databases. The primary outcome was the overall complication rate (any complication in the perioperative period), and secondary outcomes were 1) hemorrhage and 2) stroke/death (all hemorrhagic/ischemic strokes and/or death).

RESULTS

Thirteen articles including 142 patients met inclusion criteria. Eighty-nine (62.7%) patients underwent early deployment of flow diverters (i.e., 2 days or less). The odds ratio for overall complication rate with early versus delayed flow diversion was 0.95 (95% confidence interval [CI] 0.36-2.49, P = 0.42). The odds ratio for the secondary outcome of hemorrhagic complication for early versus delayed flow diversion was 1.44 (95% CI 0.45-4.52, P = 0.87) and of stroke/death was 1.67 (95% CI 0.5-4.9, P = 0.69). The odds ratio of early versus delayed flow diversion for blister/dissecting/fusiform aneurysms was 0.82 (95% CI 0.29-2.30) and for saccular/giant aneurysms was 2.23 (95% CI 0.17-29.4). At last follow-up, 71.6% of patients had good performance status (modified Rankin Scale score 0-2), and the rate of angiographic aneurysm occlusion was 90.2%.

CONCLUSIONS

This meta-analysis did not show a difference in overall complication rate between early versus delayed flow diversion for ruptured aneurysms. Early flow diversion for ruptured blister/fusiform/dissecting aneurysms carries a lower risk of aneurysm rerupture and overall complications as compared with that for ruptured saccular/giant aneurysms.

Treatment of intracranial aneurysms using the pipeline flex embolization device with shield technology: angiographic and safety outcomes at 1-year follow-up

PURPOSE

The Pipeline Embolization Device (PED) is a routine first-line treatment option for intracranial aneurysms (IAs). The Pipeline Flex Embolization Device with Shield Technology (Pipeline Shield) is an updated version of the PED which has been modified to include a surface phosphorylcholine biocompatible polymer. Its early technical success and safety have been reported previously. Here, we assessed the long-term safety and efficacy of the Pipeline Shield for the treatment of IAs.

MATERIALS AND METHODS

The Pipeline Flex Embolization Device with Shield Technology (PFLEX) study was a prospective, single-arm, multicenter study for the treatment of unruptured IAs using the Pipeline Shield. The primary endpoint was a major stroke in the territory supplied by the treated artery or neurologic death at 1-year post-procedure. Angiographic outcomes were also assessed by an independent radiology laboratory at 6 months and 1 year.

RESULTS

Fifty patients (mean age, 53 years; 82% female) with 50 unruptured IAs were treated. Mean aneurysm diameter was 8.82±6.15 mm. Of the target aneurysms, 38/50 (76%) were small (<10 mm), 11/50 (22%) were large (≥10 and<25 mm), and 1/50 (2%) was giant (≥25 mm). Forty-seven (94%) were located in the internal carotid artery and three (6%) in the vertebral artery. At 1-year post-procedure, no major strokes or neurologic deaths were reported, and complete occlusion was achieved in 27/33 (81.8%). There were no instances of aneurysm recurrence or retreatment.

CONCLUSIONS

Our 1-year follow-up concerning angiographic and safety outcomes corroborate previous evidence that the Pipeline Shield is a safe and effective treatment for IAs.

TRIAL REGISTRATION NUMBER

NCT02390037.

47 Consecutive Cases of Pipeline Flex Flow Diversion Utilizing a Novel Large-Bore Intracranial Intermediate Catheter: Nuances and Institutional Experience with the Syphontrak

Background

The increasing complexity of modern neurointerventions has necessitated a shift in intracranial access techniques towards more robust distal support platforms. Here we present our experience with the Syphontrak Support Catheter (Codman Neuro, Raynham, MA, USA) in the triaxial platform for the implantation of the second-generation Pipeline Flex embolization device (PED Flex; Medtronic Neurovascular, Irvine, CA, USA).

Methods

We retrospectively identified patients who underwent PED Flex treatment utilizing the Syphontrak at a single institution. The procedural data collected included parent artery tortuosity, patient demographics, aneurysm characteristics, other equipment utilized, and catheter-related complications.

Results

A total of 47 consecutive aneurysm flow diversions were successfully performed using the Syphontrak. The patients' age ranged from 25 to 80 years (mean 57.3 ± 11.6) and 85% were women. The average aneurysm size was 4.8 ± 2.7 mm (range 2-14). All cases were in the anterior circulation, with 6 (12%) aneurysms located beyond the internal carotid artery termination. Significant cervical carotid tortuosity was present in 23% (11/47) of the cases and moderate-to-severe cavernous tortuosity (cavernous grade ≥2) in 51% (24/47) of the cases. The mean fluoroscopy time was 36.6 ± 14.8 min. In 12/47 cases (26%), vasospasm prophylaxis with intra-arterial verapamil infusion was performed. The Syphontrak was tracked to the intended distal position in all cases, with a 100% technical success of PED Flex implantation. Forty-six (98%) of the 47 patients were discharged home after an average length of stay of 1.38 days. No iatrogenic catheter-related vessel injury occurred. Transient, minor neurological morbidity occurred in 3 cases (6%) and 1 patient had a minor ischemic event (NIHSS score < 4) in the periprocedural period.

Conclusion

The Syphontrak is a new large-bore, multi-durometer intermediate catheter (IC) designed for use in modern neurointerventional procedures. We have shown its utility in 47 successful cases of PED Flex flow diversion of a wide range of complexity. The IC provides robust and atraumatic distal intracranial access while also providing an enhanced image quality with its large 0.060″ inner diameter.

Utilization of a Novel, Multi-Durometer Intracranial Distal Access Catheter: Nuances and Experience in 110 Consecutive Cases of Aneurysm Flow Diversion

BACKGROUND

Coaxial catheter support systems provide a safe and stable foundation in endovascular treatment of intracranial aneurysms. Increasingly, robust distal intracranial support is sought during complex neurointerventions. The AXS Catalyst 5 distal access catheter (Cat5) is a new intracranial catheter designed for improved trackability and stability. We report the first experience using Cat5 for aneurysm treatment by flow diversion.

METHODS

A single-center aneurysm database was reviewed for cases of aneurysm treatment with the Pipeline embolization device (PED) that utilized Cat5. Data were collected for patient demographics, aneurysm characteristics, procedural details, catheter positions, vessel tortuosity, and catheter related complications.

RESULTS

One hundred and ten cases of aneurysm flow diversion were successfully performed using Cat5. Patient age ranged from 21 to 86 years (mean 57 ± 12.5 years) with 84% women. Aneurysm size ranged from 2 to 28 mm (mean 5.7 ± 5.0 mm), with 97% in the anterior circulation. Twenty-four aneurysms (22%) were located beyond the ICA termination. Significant cervical carotid tortuosity was present in 26% of cases, and moderate to severe cavernous tortuosity (cavernous grade ≥2) in 45% of cases. Cat5 was tracked to the intended distal position in all cases with 100% technical success of PED implantation. No iatrogenic catheter-related vessel injury occurred, and major neurological morbidity occurred in 1 patient (1%).

SUMMARY

The Cat5 is a novel, multi-durometer cranial distal access catheter designed for use in tri-axial systems. We have demonstrated the utility of Cat5 in 110 successful cases of flow diversion with a wide range of complexity. This catheter is a new tool in the neurointerventionalist's armamentarium to achieve robust and atraumatic distal access.